The present invention relates to a dual-fuel injector for a fuel injection device, in particular a combustion engine, in accordance with the preamble of claim 1. In particular, the dual-fuel injector can be used with ignition jet engines, which, in addition to an ignition jet mode using combustion gas (and a liquid fuel ignition jet), provide a pure liquid fuel mode. Diesel fuel, heavy oil or bio oil can be provided as a liquid fuel, for example.
In dual-fuel injectors of the type in question, which use liquid fuel for (indirect) control of the gas injector unit (the principle being pilot valve—actuator—control chamber), especially those which make use of high-pressure gas injection in combination with jet ignition by means of liquid fuel, there is often a not inconsiderable quantity of mixture leakage, i.e. via the guide of the respective gas nozzle needle, via which the gas nozzle chamber communicates with the control chamber. The gas component of this mixture leakage is separated out in separators, wherein the liquid fuel is fed back into the tank and the gas is re-compressed or introduced into the intake tract of the engine. This is disadvantageously complex.